Abstract: Because of the popularity of high fat diet, the global prevalence of obesity and related metabolic comorbidities has increased considerably over the past decades. Growing evidence has implicated that the gut microbiota is closely related with obesity and associated metabolic disturbances induced by high fat diet. The composition of the gut microbiota can fluctuate markedly within an individual and between individuals, because of genetic and environmental factors (diet, drug administration and lifestyle). Diet provides nutrients for humans and animals, and the microbes in the gastrointestinal tract obtain their nutrients from food sources such as dietary fibres. It has already been confirmed that diet modulates the composition and functions of the gut microbiota in humans and other mammals. The gut microbiota participates in host functions that are related to the development of obesity, including energy harvest and expenditure, gut permeability and some inflammatory and immune reactions. In this review, we discuss current studies on mechanistic interactions between the gut microbiota and metabolic health, with the aim to clarify the underlying mechanisms. Despite the growing evidence describing the role of the gut microbiota in metabolic health, more investigations are needed to substantiate whether a causeand- effect relationship exists. And the evidence linking gut microbiota to host metabolism could allow for the development of new therapeutic strategies based on gut microbiota modulation to treat or prevent obesity and related metabolic comorbidities.

Key words: high fat diet, gut microbiota, obesity, insulin resisitance, metabolic syndrome